Products used in heating/ventilation/air conditioning (HVAC) units are typically formed of sheet stock such as sheet metal. Examples of metals include steel, aluminum and the like. In particular, pipe or duct work for HVAC units is typically made from one or more sections of sheet stock that are formed to create a conduit. In general, duct work or conduit may have a round and/or rectangular cross section. The sections of steel conduit are joined to create the duct work. Flexible ducts (also known as flex) are typically made of flexible plastic over a metal wire coil to shape a tube. They have a variety of configurations. Flexible duct is very convenient for attaching supply air outlets to the rigid duct work or duct work fittings. A fitting is a sheet metal piece used to connect two pieces of ductwork and/or other fittings. Typically, flexible duct is secured to rigid duct work or fittings using zip ties.